Safety device for motor-operated systems

Abstract

A safety device for externally driven systems for protecting the movement of a system component against undesired collision with an object lying in the movement path of the system component is described, the system component to be monitored being capable of being moved in a guided fashion along a predetermined path (door plane ET). The movement path of a leading edge of a system component is preferably monitored by an optical beam protection, preferably on the basis of infrared beams, which protection has at least two, preferably at least three or a plurality of preferably parallel beams which are arranged staggered in the direction of movement of the system component and which are emitted on one side of the system component and received or reflected on the other side. The safety device has a safety circuit with which the movement of the system component is stopped or reversed if an obstacle is sensed in the movement path of the system component. The beam protection is arranged in such a way that the beam area (E) defined by the beams has at least one line in common with the movement area through which the leading edge passes, and in that the autonomously operating safety device has a beam-state control device which assigns different activation states (X, ZERO, 1) to the beams as a function of the position and of the movement of the system component.

What is claimed is:  
     
       1. A method for controlling the movement of a system component along a predetermined movement path defined by a component frame using an autonomous monitoring device that detects a position of said component and detects foreign objects in the movement path of the component to avoid an undesired collision, said monitoring device emitting a plurality of beams from transmitters to receivers, each beam being transmitted from a respective transmitter towards a respective receiver, the method including the steps of: 
       arranging said transmitters and said respective receivers with respect to said system component frame so that the beams transmitted therebetween travel across or traverse the movement path of the system component to define a monitoring field;  
       detecting the moving system component in the monitoring field according to the interruption of beams by said system component;  
       assigning a status to each said beam according to whether said system component has interrupted the beam as the system component moves along the movement path, the portion of the monitoring field defined at least by the beams interrupted by said system component being a non-monitored partial region of the monitoring field and a remaining portion of the monitoring field having beams that have not been interrupted by said system component defining a monitored partial region;  
       monitoring said monitored partial region of the monitoring field toward which the system component is moving, but into which the system component has not yet passed, to detect a foreign object in the movement path of the system component to avoid an undesired collision; and  
       stopping or reversing the movement of the system component if a beam in the monitored partial region of the scanning field is interrupted.  
     
     
       2. The method according to claim  1 , further comprising the step of determining the position of the system component on the basis of one or more detection signals obtained in the detecting step in order to determine the monitored partial region of the monitoring field. 
     
     
       3. The method according to claim  1 , wherein the assigning step comprises assigning one of a plurality of activation states to the transmitters and receivers of the monitoring device on the basis of the one or more detection signals obtained in the detecting step. 
     
     
       4. The method according to claim  3 , wherein the step of assigning includes the step of assigning a passive state (X) to those transmitters, receivers or pairs thereof, the beams of which the system component has interupted. 
     
     
       5. The method according to claim  3 , wherein the step of assigning includes the step of assigning a transition state (ZERO) to the transmitter, receiver or pair thereof of which the corresponding beam will be crossed next during the movement of the system component along the movement path. 
     
     
       6. An autonomous safety device for externally operated systems for protecting a moving system component against undesired collision with an object lying in the movement path of the system component, the system component to be monitored selectively moving along a predetermined movement path defined by a system component frame, the device including: 
       a plurality of transmitters and receivers for transmitting a plurality of beams from said transmitters to said receivers, said beam being transmitted from respective transmitters towards respective receivers, said transmitters and said respective receivers being located at, and with respect to said component frame so that the beams transmitted therebetween travel across or traverse the movement path of the system component to define a monitoring field in such a manner that, during movement of said moving system component, said beams are successively interrupted and successively released, respectively, one after the other, by said moving system component; and  
       a safety circuit for stopping or reversing the movement of the system component solely upon interruption of a beam in a part of the movement path of the system component into or through which the system component has not yet passed, by an object other than said system component.  
     
     
       7. A safety device as is claimed in claim  6 , wherein the plurality of transmitters and receivers comprise a photoelectric area sensor. 
     
     
       8. The safety device as claimed in claim  6 , further comprising a beam state control device which assigns one of plurality of activation states (X, ZERO, 1) to the beams as a function of the position and the movement of the system component, and wherein the beam-state control device assigns at least the beam which is nearest to the leading edge but is not interrupted by the system component an inactive transition state (ZERO) between an active state (1) and a passive state (X). 
     
     
       9. The safety device as claimed in claim  8 , wherein a circuit is provided which, as the system component interrupts, during its movement, the at least one beam which is in the transition state (ZERO), changes the next beam in the direction of movement of the system component film the active state (1) to the transition state (ZERO). 
     
     
       10. An autonomous safety device for externally operated systems for protecting a moving system component against undesired collision with an object lying in the movement path of the system component, the system component to be monitored selectively moving along a predetermined movement path defined by a system component frame, the device including: 
       a plurality of transmitters and receivers for transmitting a plurality of beams from said transmitters to said receivers, each beam being transmitted from a respective transmitters towards a respective receivers, said transmitters and said respective receivers being arranged with respect to said component frame so that the beams transmitted therebetween travel across or traverse the movement path of the system component to define a monitoring field;  
       a safety circuit for stopping or reversing the movement of the system component solely upon interruption of a beam in a part of the movement path of the system component into or through which the system component has not yet passed, by an object other than said system component; and  
       a beam state control device which assigns one of plurality of activation states (X, ZERO, 1) to the beams as a function of the position and the movement of the system component, and wherein the beam-state control device assigns at least the beam which is nearest to the leading edge but is not interrupted by the system component an inactive transition state (ZERO) between an active state (1) and a passive state (X).  
     
     
       11. The safety device as claimed in claim  10 , wherein a circuit is provided which, as the system component interrupts, during its movement, the at least one beam which is in the transition state (ZERO), changes the next beam in the direction of movement of the system component from the active state (1) to the transition state (ZERO).